Sewer Rehab in Mexico City
AOC Aliancys and INBODE recently collaborated to rehabilitate part of Mexico City’s wastewater infrastructure using cured-in-place pipe (CIPP) technology.
AOC Aliancys is a leading global supplier of quality polyester and vinyl ester resins, gel coats, colorants, and additives for composites and cast polymers. INBODE is a contractor for trenchless rehabilitation in Mexico and also sells, rents and services hydro pneumatic sewer cleaning equipment, sewage pumps and drainage inspection equipment.
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In March 2018, Mexico City’s Water utility SACMEX contracted INBODE to rehabilitate 209.5 of pipeline in the area of “Rio Chico” in the Tizapán region of the Álvaro Obregón borough of Mexico City. SACMEX (Sistema de Aguas de la Ciudad de Mexico) is Mexico City’s water system operator, providing potable water, drainage, sewage, wastewater treatment and water reuse services. It is responsible for the operation, maintenance, infrastructure, development and distribution of Mexico City’s water resources. The 50-year-old segment of pipeline running 2.13m (84 in.) in diameter had suffered irreversible structural damage due to the continual caving of land above. The damage was disrupting the pipeline from efficiently conducting wastewater from the Texcalatlaco Dam and surrounding areas to port No. 12 of SACMEX’s west interceptor.
The Problem
To determine the severity of structural damage to the pipeline, INBODE performed a CCTV video inspection, which identified a high degree of deterioration, fissures, cracks and drag — causing water to escape into the surrounding earth and generate shifting and sinkholes.
The Solution
The CIPP installation presented great challenges in engineering and logistics. INBODE installed a polyester felt liner that was 2.13 m (84 in.) in diameter with a high-density polyurethane coating and a thickness of 36 mm — reinforced at specific points to 46.5 mm, with a total length of 209.5 m. The liner was impregnated with 61,235 Kg (135,000 lbs) of AOC’s Vipel L704-TAP-30, a thermally activated isophthalic polyester resin manufactured by AOC in Mexico. L704-TAP-30 was specifically developed for use in rehabilitating large diameter pipes and provides the corrosion resistance, durability and toughness required for CIPP applications.
INBODE installed a polyester felt liner that was 2.13 m (84 in.) in diameter with a high-density polyurethane coating and a thickness of 36 mm.
Challenges
A mobile warehouse was installed on site to manage the short disruption of service and execute the complex installation more easily. A bypass pumping system was installed to re-direct 2,200 lps (liters per second) of wastewater and provide the conditions necessary for liner installation.
Before the CIPP process could begin, a comprehensive cleaning and inspection was needed. INBODE used hydro pneumatic sewer cleaning equipment to clear up to half a ton of accumulated silt, stones, tree branches and other debris that were obstructing flow. Prior to liner installation, IMBODE performed a final video inspection to ensure the removal of all debris, identify service connections and assess pipe conditions. The host pipe was now ready for the liner to be introduced.
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The liner was impregnated with 61,235 Kg (135,000 lbs) of AOC’s Vipel L704-TAP-30, a thermally activated isophthalic polyester resin manufactured by AOC in Mexico.
Installation
IMBODE impregnated the liner with Vipel L704-TAP-30 resin on-site using equipment, which included: an automated static mixer for introducing the resin and catalysts; a vacuum system, calibration rollers; a 6.9 m inversion column to ensure even application to the host pipe; and a boiler truck with a capacity of 40 million BTUs (heat units) all operated by specialized personnel according to ASTM F1216-16 standards. AOC representatives were on-site through every step to offer the customer support, technical expertise and product insight to ensure a successful installation.
Results
The CIPP rehabilitation of the Chico Rio pipeline successfully restored crucial function to the pipeline more effectively than open cut methods — while avoiding the time, expense, environmental impact, and disruption to the daily activities of residents, businesses and services. The rehabilitated pipeline also is totally continuous and structurally and chemically resistant to corrosive wastewater environments — which reduces operating and maintenance costs.
Leslie Beck is director of global communications for AOC LLC.
